The Minimal Seesaw Model at the TeV Scale

TL;DR

This paper explores a minimal seesaw model at the TeV scale, demonstrating its ability to naturally generate tiny neutrino masses, predict inverted hierarchy, and produce testable low-energy and collider signatures.

Contribution

It shows that the minimal seesaw model can naturally accommodate tiny neutrino masses and inverted hierarchy while remaining experimentally testable and predictive.

Findings

Tri-bimaximal mixing with inverted hierarchy is achievable.

Non-unitarity effects in neutrino oscillations are significant.

Collider signatures of heavy neutrinos are discussed.

Abstract

We point out that the minimal seesaw model can provide a natural framework to accommodate tiny neutrino masses, while its experimental testability and notable predictiveness are still maintained. This possibility is based on the observation that two heavy right-handed Majorana neutrinos in the minimal seesaw model may naturally emerge as a pseudo-Dirac fermion. In a specific scenario, we show that the tri-bimaximal neutrino mixing can be produced, and only the inverted neutrino mass hierarchy is allowed. The low-energy phenomena, including non-unitarity effects in neutrino oscillations, neutrinoless double-beta decays and rare lepton-flavor-violating decays of charged leptons l_alpha to l_beta + gamma, have been explored. The collider signatures of the heavy singlet neutrino are also briefly discussed.